1. Field of the Invention
The present invention relates to a method for manufacturing a balloon catheter, and more particularly, the present invention relates to a method for manufacturing a balloon catheter which is, as a medical appliance, fitted into a tube-shaped organ of the body and a portion of which is maintained in an expanded state to allow liquid medicine to be injected therein and liquid excrement to be removed therefrom.
2. Description of the Related Art
Generally, a balloon catheter is made of silicone to be medically superior. A method for manufacturing a balloon catheter will be described hereinafter with reference to U.S. Pat. No. 5,137,671.
Referring to the drawings, a tube 10 as shown in FIG. 1 is provided. The tube 10 is formed with a first lumen 14 (a capillary tube of a smaller diameter) and a second lumen 12 (a tube of a larger diameter).
In a state that the tube 10 as described above is prepared, a middle portion of the tube 10, that is, a balloon expansion section of the tube 10 is, as shown in FIG. 2, formed with a first hole 16 which communicates an inside of the first lumen 14 with an outside of the tube 10. Then, polymeric filler material 18 such as silicone rubber is filled into a part of the first lumen 14 which extends from a lower end of the first lumen 14 to a point where the first hole 16 is defined, and a tip member 20 is attached to a lower end of the tube 10 from which the polymeric filler material 18 is filled into the first lumen 14, whereby lower ends of the first and second lumens 14 and 12 are closed.
Thereafter, a part of the tube 10 which extends from the lower end thereof and to an upper end of the balloon expansion section as shown by the line A--A in FIG. 3, is dipped into releasing agent solution (such as soapy water, Vaseline solution or the like), and the releasing agent solution is solidified to leave releasing agent 30 onto the part of the tube 10. At this time, releasing agent 30 is filled into the first hole 16 and another part of the first lumen 14 which extends from the point where the first hole 16 is defined to the upper end of the balloon expansion section as shown by the line A--A in FIG. 3. Consequently, the tube 10 has a cross-section as shown in FIG. 3. That is to say, the releasing agent 30 is filled into the first lumen 14 from the upper end of the balloon expansion section as shown by the line A--A in FIG. 3 to the first hole 16, and is coated onto an outer surface of the tube 10 between the upper end of the balloon expansion section as shown by the line A--A in FIG. 3 and the end of the tip member 20 as shown in FIG. 3.
Then, as shown in FIG. 4, another part of the tube 10 which extends from the lower end thereof to the lower end of the balloon expansion section as shown by the line B--B in FIG. 4 is dipped again into water or hot liquid, to remove the releasing agent coated onto the outer surface of the tube 10 except the balloon expansion section, and a first over-coating layer 41 and a second over-coating layer 42 are sequentially coated onto an entire outer surface of the tube 10, to define an over-coating layer 40.
Then, the releasing agent which is filled into the first lumen 14 and the first hole 16 and coated onto the outer surface of the balloon expansion section, is removed through the first lumen 14, thereby defining a space part 44 as shown in FIG. 6 for allowing the balloon expansion section to be expanded.
However, when a balloon catheter is manufactured by the processes of the conventional art, as described above, an amount of waste water which is generated when removing the releasing agent coated onto the outer surface of the tube 10 except the balloon expansion section after dipping the tube 10 into releasing agent solution, is increased in the course of dipping the tube 10 into water, etc. through a number of times, thereby causing environmental pollution.
Further, in the case that the releasing agent is not perfectly removed, when the balloon expansion section is expanded after the space part is formed, a portion of the over-coating layer adjoining the balloon expansion section is peeled off, thereby to be expanded together with the balloon expansion section.